1. Field of the Invention
The present invention relates to a golf club with a head made of a plastic material, or a fiber reinforced plastic material, fitted to a metal core member.
2. Description of the Related Art
Recently, proposals have been made for a golf club having a head made of a plastic material, or a fiber reinforced plastic material, and such golf club head is known, for example, as a "carbon head". This type of plastic golf club head is light in weight and can be easily formed into a desired shape, and usually, a metal core member is incorporated in the plastic golf club head to adjust the center of gravity and increase the rigidity of the head. For this purpose, the metal core member is formed in a shape of a core body portion and a neck portion integrally extending from the core body portion. The plastic head is formed by molding the plastic material together with the metal core member inserted therein, whereby the plastic outer member is molded around the metal core member. In many cases, the plastic outer member fully covers the metal core member except at the sole portion of the head. Namely, the hitting portion is constituted by the plastic outer member and the sole portion is a part of the metal core member. The neck portion of the metal core member is fully covered by the plastic outer member.
An example of a conventional plastic head is shown in FIG. 5, in which the head 1 comprises a hitting portion la and a neck portion lb and is fitted to a shaft 2. The metal core member is composed of a core body portion 3a, a neck portion 3b and a sole portion 3c. A plastic or fiber reinforced plastic outer member 4 covers the metal core member portions 3a and 3b but does not cover the sole portion 3c. A bore 5 is provided in the neck portion 3b of the metal core member and a plastic socket 6 is fitted on the shaft 2 and abuts against the upper end of the neck portion 1b of the head.
In the manufacture of a golf club, it is sometimes necessary to adjust the loft angle and lie angle of the club head by bending the neck portion of the club head after the club head has been made. Accordingly, a problem arises in the above described plastic head having a composite structure, in that the plastic or fiber reinforced plastic outer member is separated at the neck portion of the metal core member when the neck portion of the club head is bent for adjustment or damaged by the clamping force used when bending the neck portion.